A sprocket of a track laying implement is rotatably driven in opposite rotational directions and includes a plurality of teeth which engage an endless track chain including trackpins and bushings articulately interconnecting like track sections. Each sprocket tooth has a predetermined initial profile defined by a tip with opposite track engaging surfaces extending therefrom and toward a tooth root.
Wear on the sprocket teeth results from contact with the track chain as well as the abrasiveness of dirt, rocks, and other debris material entrapped or packed therebetween. More specifically, sliding vertical contact with the track bushings during forward and reverse directional movements of the track chain causes wearing of the tooth root. Sliding contact with the track bushings likewise causes wear on reverse and forward sides of each sprocket tooth. Uneven terrain and side hills, turning of the implement, improper width of track link shoes, and the like, furthermore causes sprocket tooth corners to wear.
When the wear pattern remains within the side surfaces of the tooth, the sprocket remains usable. When the wear pattern, however, extends into the tip of the tooth, positive engagement of the sprocket teeth into the track chain is adversely effected, and the track chain may jump over the teeth. This causes extreme shock loads which could damage the track components. Accordingly, excessive wear of the sprocket tooth profile normally requires replacement of the sprocket.
Different forms of gauges have been heretofore utilized for attempting to determine whether the sprocket remains usable or has been worn to an extent requiring replacement. Such gauges have normally required accurate and proper placement between the sprocket teeth to measure wear as a function of the gap between the gauge and the sprocket teeth. Besides the problem of accessibility to gauge sprocket tooth wear, such gauges are not reliable as a means of measuring sprocket wear because the sprocket teeth have no clear reference point from which to take a measurement. Thus, such gauges normally result in a misreading of the actual extent of wear of the sprocket.
Thus, there remains a need and a desire for a sprocket wear indicator which does not rely on proper placement of a gauge between adjacent teeth of the sprocket and yet which provides an accurate measurement of sprocket wear.